Flexible metal pipe.



M. PECHSTEIN.

FLEXIBLE METAL PIPE.

, APPLICATION FILED NOV- I3. 1913. 15,145,434.

Patented-July 6, 1915 UNITED sTATEs PATENT oEEIoE.

MAX PECHSTEIN, 0F ZWICKAU, GERMANY, ASSIGNOR TO THE FIRM 0F LOUISBLUMER, OF ZWICKAU, GERMANY.

FLEXIELE METAL PIPE.

Specification of Letters Patent.

Patented July 6, 1.915o

To all whom 'it may concern.'

.Be it known that I, MAX PEoHsTEIN, a subject of the King of Saxony, andresident of Zwickau, Germany, have invented certain new and usefulImprovements in Flexible Metal Pipes, of which the following is aspecification.

This invention relates to improvements in flexible metal pipes, of thetype in which the grooves in the interior of the metal pipe are coveredby a spiral, of which the edges overlap each other in scale-like manner.The known Hexible metal pipes of this kind have the drawback that thespiral cannot be tightened between its overlapping ends. The presentinvention overcomes this drawback by providing between the overlappingedges of the spiral a continuous tightening groove with packing materialtherein in such a way that the spiral can, independently of the outerpipe, be so tightened that any penetration of fluid or the like throughthe overlapping ends is impossible, the smooth inner surface of themetal pipe being not affected by this arrangement. The outer material ofthe spiral surrounding said groove, which for the purpose of providingthe latter therein is bulbed toward the outside, bears without play uponcorresponding grooves in the .inside of the metal pipe, so that thespiral 1s compelled to exactly participate in the movements of the outermetal pipe.

The accompanying drawing shows in Figures l to 3 fragmentarycross-sections of three suitable constructional forms of a metal pipefitted with the improved spiral, a being the continuous groove withpacking material in the spiral and b the corresponding bearings in themetal pipe.

What I claim, is:

A flexible metal pipe, comprising in cornbination, an outer metal pipe,grooved bearings on the inner surface of the same, a spiral withoverlapping ends within the metal pipe having a continuous packinggroove between said overlapping ends, the outer material of said groovedesigned to engage, without play, with said grooved bearings,substantially a and for the purpose set forth.

MAX PECHSTEIN.

W'itnesses:

ELPRED J. MAGEE. HANS MUGKE.

